scholarly journals Microbial community similarity and dissimilarity inside and across full-scale activated sludge processes for simultaneous nitrification and denitrification

2020 ◽  
Vol 81 (2) ◽  
pp. 333-344
Author(s):  
Jianfeng Wen ◽  
Mark W. LeChevallier ◽  
Wendong Tao
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Relative Abundance ◽  
Nitrogen Removal ◽  
Full Scale ◽  
Batch Reactors ◽  
Simultaneous Nitrification And Denitrification ◽  
Sequencing Batch Reactors ◽  
Mixed Liquor

Abstract Simultaneous nitrification and denitrification under low dissolved oxygen conditions is an energy-saving modification of the activated sludge process to achieve efficient nitrogen removal. Geographically distinct full-scale treatment plants are excellent platforms to address the links of microbial community with operating parameters. Mixed liquor samples were collected from a sequencing batch reactor plant, oxidation ditch plant, and step-feed activated sludge plant. Next-Generation Sequencing of the samples showed that the microbial communities were similar at the phylum level among the plants, being dominated by Proteobacteria. Microbial composition of functional groups was similar between the react fill and react phases of the sequencing batch reactors, among four sequencing batch reactors, and among four oxidation ditches. Nitrospira was the only identified genus of autotropic nitrifying bacteria with a relative abundance of 2.2–2.5% in the oxidation ditches and 0.4–0.7% at the other plants. Heterotrophic nitrifying–aerobic denitrifying bacteria were dominated by Dechloromonas with a relative abundance of 0.4–1.0%. Microbial community composition and nitrogen removal mechanisms were related to overall level and local zonation of dissolved oxygen, mixed liquor suspended solids concentration, nitrogen and organic loadings, and solids retention time. Low dissolved oxygen and low organic and nitrogen loadings favored growth of Nitrospira.

scholarly journals Seasonal Dynamics of the Activated Sludge Microbiome in Sequencing Batch Reactors, Assessed Using 16S rRNA Transcript Amplicon Sequencing

2020 ◽  
Vol 86 (19) ◽  
Author(s):  
Juliet Johnston ◽  
Sebastian Behrens
Keyword(s):  
Wastewater Treatment ◽  
Microbial Community ◽  
16S Rrna ◽  
Activated Sludge ◽  
Seasonal Dynamics ◽  
Activity Patterns ◽  
Amplicon Sequencing ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Copy Numbers

ABSTRACT Activated sludge is comprised of diverse microorganisms which remediate wastewater. Previous research has characterized activated sludge using 16S rRNA gene amplicon sequencing, which can help to address questions on the relative abundance of microorganisms. In this study, we used 16S rRNA transcript sequencing in order to characterize “active” populations (via protein synthesis potential) and gain a deeper understanding of microbial activity patterns within activated sludge. Seasonal abundances of individual populations in activated sludge change over time, yet a persistent group of core microorganisms remains throughout the year which are traditionally classified on presence or absence without monitoring of their activity or growth. The goal of this study was to further our understanding of how the activated sludge microbiome changes between seasons with respect to population abundance, activity, and growth. Triplicate sequencing batch reactors were sampled at 10-min intervals throughout reaction cycles during all four seasons. We quantified the gene and transcript copy numbers of 16S rRNA amplicons using real-time PCR and sequenced the products to reveal community abundance and activity changes. We identified 108 operational taxonomic units (OTUs) with stable abundance, activity, and growth throughout the year. Nonproliferating OTUs were commonly human health related, while OTUs that showed seasonal abundance changes have previously been identified as being associated with floc formation and bulking. We observed significant differences in 16S rRNA transcript copy numbers, particularly at lower temperatures in winter and spring. The study provides an analysis of the seasonal dynamics of microbial activity variations in activated sludge based on quantifying and sequencing 16S rRNA transcripts. IMPORTANCE Sequencing batch reactors are a common design for wastewater treatment plants, particularly in smaller municipalities, due to their low footprint and ease of operations. However, like for most treatment plants in temperate/continental climates, the microbial community involved in water treatment is highly seasonal and its biological processes can be sensitive to cold temperatures. The seasonality of these microbial communities has been explored primarily in conventional treatment plants and not in sequencing batch reactors. Furthermore, most studies often only address which organisms are present. However, the activated sludge microbial community is very diverse, and it is often hard to discern which organisms are active and which organisms are simply present. In this study, we applied additional sequencing techniques to also address the issues of which organisms are active and which organisms are growing. By addressing these issues, we gained new insights into seasonal microbial populations dynamics and activity patterns affecting wastewater treatment.

Demonstration of enhanced nutrient removal at two full-scale SBR plants

2004 ◽  
Vol 50 (10) ◽  
pp. 115-120 ◽  
Author(s):  
M. Peters ◽  
M. Newland ◽  
T. Seviour ◽  
T. Broom ◽  
T. Bridle
Keyword(s):  
Nutrient Removal ◽  
Full Scale ◽  
Biological Nutrient Removal ◽  
Batch Reactors ◽  
Simultaneous Nitrification And Denitrification ◽  
Sequencing Batch Reactors ◽  
Operational Control ◽  
The World ◽  
High Level ◽  
Operational Data

The efficacy of sequencing batch reactors (SBRs) to provide high levels of biological nutrient removal has been extensively demonstrated around the world. Environmental Solutions International (ESI) has now constructed over 20 full-scale SBR plants and has confirmed that nutrient removal is enhanced via the process of simultaneous nitrification and denitrification. Over 18 months of operational data from two plants, operating in distinctly different catchments, processing an average of between 2,000 and 2,500 m3/d of wastewater, has clearly shown the efficacy and robustness of the ESI SBR-BNR process. Median effluent total nitrogen and total phosphorus values of 3 mg/L and <0.6 mg/L, respectively, were demonstrated over the 18-month period. This high level of nutrient removal is attributed to the design of the bio-selector which maximises carbon storage for the subsequent denitrification reactions, the effective aeration control which ensures no over-aeration during the air-on cycle as well as the level of operational control provided at these two plants.

Effects of dissolved oxygen on sludge reduction and microbial community structure in sequencing batch reactors

2019 ◽  
Vol 161 ◽  
pp. 56-65
Author(s):  
Yufeng Xu ◽  
Long Wang ◽  
Xiaofeng Yin ◽  
Shengkun Zhang ◽  
Simin Li ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Dissolved Oxygen ◽  
Microbial Community Structure ◽  
Batch Reactors ◽  
Sludge Reduction ◽  
Sequencing Batch Reactors

Simultaneous Nitrification/Denitrification in a Single Reactor using Ciliated Columns Packed with Granular Sulfur

2005 ◽  
Vol 40 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Yong-Woo Hwang ◽  
Chang-Gyun Kim ◽  
In-Jun Choo
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Glass Beads ◽  
Denitrification Rate ◽  
The Other ◽  
Simultaneous Nitrification And Denitrification ◽  
Total Nitrogen Removal ◽  
Anoxic Zones

Abstract This study was conducted to assess the possibility of simultaneous nitrification and denitrification in an activated sludge using a cilia media packed with granular sulfur in a single reactor. For the granular sulfur column adopted, the total nitrogen removal was up to 67%. This facilitated the simultaneous decomposition of autotrophic and heterotrophic denitrifiers present at a 5:2 ratio. On the other hand, the control incubation test employing glass beads achieved only 18% denitrification. Regardless of the NH4-N loadings, the use of ciliated granular sulfur columns, made denitrification 1.5 times faster than when cilia was not used. The size of the granular sulfur columns directly contributed to the extent of denitrification, which was correlated to the void sphere of anoxic zones through the columns. Dissolved oxygen (DO) concentrations lower than 4.0 mg/L did not influence the level of denitrification. However, when higher than 4.0 mg/L, the DO began to negatively impact the denitrification rate. The study found that the simple installation of a cilia media packed with granular sulfur in an existing activated sludge could simultaneously achieve an efficient nitrification/denitrification in a single reactor.

Effect of salinity on the activity, settling and microbial community of activated sludge in sequencing batch reactors treating synthetic saline wastewater

2008 ◽  
Vol 58 (2) ◽  
pp. 351-358 ◽  
Author(s):  
G. Wu ◽  
Y. Guan ◽  
X. Zhan
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Volume Index ◽  
Synthetic Wastewater ◽  
Utilization Rate ◽  
Yield Coefficient ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Saline Wastewater ◽  
Sludge Flocs

The effects of salinity on the activity in nutrient removal, settling and microbial community of activated sludge in sequencing batch reactors (SBRs) treating synthetic saline wastewater were investigated. Two SBRs, one treating synthetic saline wastewater (the N-Reactor, with NaCl addition) and the other treating fresh synthetic wastewater (the C-Reactor, without NaCl addition), were operated for 68 days. Three salinities (in terms of concentrations of NaCl)—10, 20 and 40 g NaCl/l—were examined. The microbial activity described with the specific glucose utilization rate, specific nitritation and nitratation rates, and specific phosphorus release and uptake rates, was inhibited in the N-Reactor, in comparison with that in the C-Reactor, except that the specific nitritation and nitratation rates were improved at the salinity of 10 g NaCl/l. The sludge yield coefficient decreased at salinities of 10 and 20 g NaCl/l but it rose at the salinity of 40 g NaCl/l. The settling of activated sludge flocs, in terms of the sludge volume index (SVI), was improved by adding NaCl. Particularly in the first 5 minutes during the SVI measurement, activated sludge flocs in the N-Reactor settled much faster than those in the C-Reactor. However, the effluent from the N-Reactor contained higher suspended solids than the effluent from the C-Reactor. The microbial diversity decreased with increasing the salinity, and the microbial community structure was greatly influenced by the salinity. Bacteriodetes and Actinobacteria were the dominant phylums detected with molecular fingerprinting techniques.

Short term effects of dissolved oxygen concentration on the turbidity of the supernatant of activated sludge

1998 ◽  
Vol 38 (3) ◽  
pp. 25-33 ◽  
Author(s):  
Britt-Marie Wilén ◽  
Peter Balmér
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Adsorption Capacity ◽  
Full Scale ◽  
Aeration Tank ◽  
Batch Reactors ◽  
Short Term ◽  
Colloidal Material ◽  
Do Concentration ◽  
Short Term Effects

Short term effects of dissolved oxygen (DO) concentration on the supernatant turbidity of activated sludge were studied in batch reactors, continuous reactors and in a full scale plant. Adsorption of colloidal material onto activated sludge was studied in batch reactors. The adsorption capacity of colloidal material, expressed as removal of turbidity, was larger in aerobic than in anaerobic conditions. The difference in adsorption capacity between high (≥5 mg/l) and low (<0.5 mg/l) DO concentrations was small. Experiments were made in pilot scale completely mixed reactors where the oxygen supply was turned off during different periods of length (1-4 hours). The turbidity increased directly when the anaerobic period started and decreased when the aerobic period started. Similar results were obtained when the influent was turned off. A few full scale experiments were carried out. The aerators were adjusted to change the DO concentration along the aeration tank (plug flow) for periods of 3-6 hours. Low DO concentrations by the end of the aeration tank produced a turbidity increase of the effluent, while low DO concentrations in the first half of the aeration tank did not affect the turbidity to a large extent.

scholarly journals Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2450
Author(s):  
Antonina Kruglova ◽  
Jenni Kesulahti ◽  
Khoi Minh Le ◽  
Alejandro Gonzalez-Martinez ◽  
Anna Mikola ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Microbial Community ◽  
Low Temperature ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Full Scale ◽  
Cold Climate ◽  
Microbial Community Analysis ◽  
Operational Parameter ◽  
Climate Conditions

In this study, the microbial community of nitrifying activated sludge adapted to Finnish climate conditions was studied to clarify the microbial populations involved in low-temperature nitrification. Microbial community analysis of five full-scale wastewater treatment plants (WWTPs) showed several differences compared to WWTPs from other countries with a similar climate. In particular, very low abundance of ammonium oxidizing bacteria (AOBs) (altogether ˂ 0.25% of total community) as well as typical NOBs (˂0.35%) and a high abundance of orders Cytophagales and Micrococcales was observed in all Finnish WWTPs. To shed light on the importance of autotrophic and heterotrophic nitrifying processes, laboratory studies of activated sludge were carried out with a presence of and a lack of organic carbon in wastewater at 10 ± 1 °C. Two different sludge retention times (SRTs) were compared to determine the effect of this operational parameter on low-temperature nitrogen removal. The important role of previously reported Candidatus Nitrotogaarctica for nitrite oxidizing in cold climate conditions was confirmed in both full-scale and laboratory scale results. Additionally, potential participation of Dokdonella sp. and Flexibacter sp. in nitrogen removal at low-temperatures is proposed. Operation at SRT of 100 days demonstrated more stable and efficient nitrogen removal after a sharp temperature decrease compared to 14 days SRT.

scholarly journals The influence of dissolved oxygen on partial nitritation/anammox performance and microbial community of the 200,000 m3/d activated sludge process at the Changi water reclamation plant (2011 to 2016)

2018 ◽  
Vol 78 (3) ◽  
pp. 634-643 ◽  
Author(s):  
Yeshi Cao ◽  
Bee Hong Kwok ◽  
Mark C. M. van Loosdrecht ◽  
Glen Daigger ◽  
Hui Yi Png ◽  
...  
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Water Reclamation ◽  
Process Performance ◽  
Population Abundance ◽  
Activated Sludge Process ◽  
Partial Nitritation ◽  
Do Concentration

Abstract Mainstream partial nitritation/anammox (PN/A), coupled with excess biological phosphorus removal, in a 200,000 m3/d step-feed activated sludge process (Train 2) in the Changi Water Reclamation Plant (WRP), Singapore, has been studied and reported. This paper presents an overview of process performance and the microbial community during the period from 2011 to 2016. The site data showed that, along with the reduction of dissolved oxygen (DO) from 1.7 to 1.0 mg O2/L in the aeration zones, the concentrations of ammonium and nitrate of the final effluent increased, while nitrite decreased, resulting in an increase of 2.4 mg N/L of total inorganic nitrogen. Autotrophic nitrogen removal was higher than heterotrophic biological nitrogen removal under higher DO concentration conditions, but decreased under low DO operating condition. These macro-scale changes were caused by shifts of the nitrogen-converting microbial community. The ammonia oxidizing bacteria (AOB) population abundance was reduced by 30 times, while the nitrite oxidizing bacteria (NOB) population abundance and specific activity increased significantly with a shift of dominant genus from Nitrobacter to Nitrospira. The ratio of AOB and NOB specific activities were reduced from 12.8 to 1.6, and the ex situ nitrite accumulation ratio reduced from 76% to 29%. Changes in the microbial community and overall process performance illustrated that, compared to the excellent NOB suppression under high DO conditions, NOB were more active after the DO concentration reduction despite still being partly suppressed. This case study demonstrated, for the first time, the influence of DO reduction on the nitrogen conversion microbial community and PN/A process performance for a suspended growth system. Its relevance to biofilm and hybrid PN/A processes is also discussed.

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